In a recent diary the topic of roasting vegetables came up in the comments and it inspired me to dig into the ol’ WFD archives because I knew, just knew, that an old contributor around these parts just HAD to have covered the topic with his scientific know-how. Sure enough, I was correct!
Translator, a long-time contributor here, often combined his background in science and his love of cooking here at WFD. He wrote very simply of the method; the how and the why coming along for a ride with the fascinating science behind it. So let’s start there. . .
Fair warning: Geeky cooking science stuff ahead! I promise we’ll get to the yummy soup!
“In roasting (baking for breads and oddly for poultry, but the process is identical), hot air from an oven transfers heat to the food to be cooked. Roasting is very inefficient as far as heat transfer goes, but gives results not possible with other methods. For one thing, there is no upper limit to how hot air can get, since it is so inert. Ovens can range from barely on to 500 degrees F or more. There is not any danger of the air catching on fire! [. . .]
Roasting is a dry method of cooking, meaning that no water is used as a heat transfer medium. Since air is around 1000 times less dense than, say, water, it transfers heat quite slowly.
Here is a thought experiment for you to try. In you mind, preheat your oven to 212 degrees F. Now put your hand inside of it, and by magick close the door so the oven stays at that temperature. I suspect that you can keep your hand inside for a LONG time before it gets painful. Now, for the second part of the thought experiment, take a large pot of water and bring it to the boil, the same 212 degrees F, and put your hand in it. See what I mean? Within one second you would not only feel horrible pain, but you would be seriously injured. That is what I mean when I talk about roasting being inefficient insofar as heat transfer is concerned.
Sometimes inefficiency is a good thing. For example, the moisture that evaporates from a nice roast keeps the outside from getting overdone before the centre cooks through. Yes, I have reverted to UK spelling! Also, since air can get really, really hot, Maillard browning reactions can occur that give bread and some wonderful meats a flavour spectrum not possible otherwise. That is sort of characteristic of dry cooking methods.
Roasting is best used for meats that are inherently tender, because this method does little to tenderize things. Poultry, being tender, roasts well, as do tender cuts of beef and pork. Tougher cuts do not do well when roasted, because the heat balance is all wrong. Of course, breads do well roasted (baked) because they are designed to be tender in the first place. In general, dry methods are good for tender meats and vegetables and wet methods for tougher cuts of meat and vegetables that tend to be either dry or tough, like beans."
Thanks Doc.
I have found lots of vegetables that I didn’t think I really liked are fantastic when roasted! If it’s a vegetable I do like then even better! You don’t need to dirty a lot of dishes and the flavor combinations are only limited by your taste buds. Here’s my rule-of-thumb basics:
- Prep your veggies as needed so that you have roughly uniform size pieces with any inedible bits trimmed off i.e. peels, stems, seeds, etc.
- Toss in a neutral oil (a light olive oil is my usual) to coat and season liberally with salt and pepper.
- Add other seasonings according to your whim. I usually stick to dried herbs and spices but hardier fresh herbs such as rosemary, thyme, tarragon, and the like should be added now while tender leafy green herbs like parsley or cilantro should be added when taken out of the oven so the flavor is not cooked out.
- Unless I’m going by a specific recipe I have found 425° seems to be the sweet spot for my oven and cooking time depends on the veg. But you do want to check about 15 minutes in and give the pan a shake or gently toss your veggies to turn and ensure they’re not getting burnt on the bottom.
- When they are tender to your preference and golden browned take them out and add any final seasonings while nice and sizzling hot. If you need to hold them for any time before serving I would leave them in the oven turned off. If you cover them the steam will condense and you get chewy instead of that nice crisp caramelized texture.
Roasted veggies are great just as they are but they become amazing ingredients too. Not to mention you can put them to twice the work by using your leftovers if you plan it right! Or you can save yourself a little bit of money, which brings us to the soup. Ohhhh. . . this soup! It turned out so good!
Roasted Red Pepper & Sweet Potato Soup
I love the sweetness of fresh red bell peppers but most of the roasted red pepper soups I’ve tried from the grocery store are just too sweet. And they are usually a combination of roasted red pepper and tomato which always seems to end up tasting like sweet tomato soup to me. I’ve played around with making my own before but only with tomatoes and Italian seasonings. It was good, but the tomato really took over. So when red bells were on sale recently I decided to go in a different direction inspired by a recipe I saw online. I like sweet potato and I know it pairs really well with smoky spices so I reached for my brand new jar of smoked paprika (yay! I finally got a bunch of amazing new stuff from Penzey’s!) and let it shine! So yes, this soup is sweet, smoky, spicy, thick, and velvety! It does require some time for the prep though, so get your ovens started!
Roast 3 large red bell peppers:
- Place your oven rack in the top third so that the peppers will lie on the rack about 6” below the heating element. Preheat the oven to Broil.
- Rinse and wipe your peppers dry. When the oven is ready place your peppers on the rack and let them blacken up on all sides, checking on them and turning as each side blackens. Think of it as grilling upside down;)
- When they are blackened all over remove them from the oven and place them in a paper bag (or a covered dish) and then close it up and let them sit for about 30 minutes.
Open up the bag and gently wipe the blackened skin off the flesh and scrape off the seeds and the core. Small bits may need a bit of scraping with your fingernail or a knife. I like to do this all in the sink. I let the bag sit then I just tear it open and scrape all the skin and stuff off right onto the bag and then put the red pepper pieces into a bowl. Wrap up the paper bag with all the discarded bits and into the trash it goes.
Voila! You now have roasted red peppers to use in stuff! Now how much do those little jars of ‘em cost? Ok, next?
Roast the sweet potatoes.
- Peel and chop 2 large sweet potatoes.
- Spread onto a large rimmed baking sheet lined with foil.
- Drizzle with olive oil and season with kosher salt, pepper, a liberal sprinkling of smoked paprika, and cumin.
- Toss to coat all pieces well.
Roast at 425° for 20-25 minutes tossing occasionally to turn until browned on the outside and easily pierced with a sharp knife.
Both of these can be done in advance. They can be stored in the fridge until you’re ready to use.
Alright then. We are ready to make some soup!
Heat 2 tbsp of olive oil in a large Dutch oven or stock pot over medium-low heat. Add the roasted sweet potatoes and red peppers to the pot.
Season with 1 tsp smoked paprika, ¼ tsp cayenne pepper, ¼ tsp crushed red pepper flake, and a little more salt and pepper. This was a nice mild-medium heat so feel free to adjust to your taste.
Pour in 4-5 cups of chicken or vegetable stock (you want it to completely cover the potatoes) and bring to a boil.
Lower heat to a simmer and cover. Let simmer for 1 hour, stirring occasionally to ensure nothing is sticking. Puree the soup with an immersion (stick) blender or in batches in a blender. Taste for seasoning, serve and enjoy!
What are you roasting (or not) for dinner tonight? Pull up a chair and welcome to our table!
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